Modern electronics, such as smart phones, personal digital assistants, location based services devices, digital cameras, music players, servers, and storage arrays, are packing more semiconductor devices into an ever-shrinking physical space with expectations for decreasing cost. One cornerstone for devices to continue proliferation into everyday life is the integration of more functions into a given area of the semiconductor device. Numerous technologies have been developed to meet these requirements.
One approach to increase the density in a semiconductor device involves a technology to transform and shrink images onto a wafer. This process is called lithography or photolithography. Lithography systems have limitations of how small images may be reduced onto a wafer and these limitations bound the minimum dimensions of the semiconductor device. Some examples of the minimum dimensions for the semiconductor device are minimum gate length, structure width, or pitch between structures.
Various types of lithography systems, such as proximity lithography, contact lithography, projection lithography, or immersion lithography, have been used to increase density in a semiconductor device. Each has their advantages and drawbacks but all have minimum dimension limitations as discussed above.
Lithography systems use a light source to transfer an image from a mask to a wafer. Different light sources, such as a ultra-violet light of different wavelengths, different mask technologies, or both to improve the density in a semiconductor device. Again, each approach has their advantages and drawbacks but all have minimum dimension limitations as discussed above.
Other approaches use different combinations of the above components of a lithography system as well as different types of materials during the manufacture of a wafer. Yet other approaches use these various components in different manufacturing processes to improve density.
For example, semiconductor manufacturing may use a light source emitting light having a 193 nm wavelength to transfer the transform patterns to the wafer. As feature size decreases, the lithographic patterns approach its resolution limit. To extend the use of a lithography system, such as 193 nm lithography system, below its resolution limit, a double exposure technique is considered. The double exposure technique generates a pattern by decomposing one mask layer to two layers and two consecutive exposures forming the desire etch pattern. These approaches have their own drawbacks, such as production throughout impact.
Thus, a need still remains for a method for manufacture of a semiconductor device providing increased density, improved yields, improved throughput, lower cost, and increased use of existing manufacturing equipments. In view of the ever-increasing need to save costs and improve efficiencies, it is increasingly critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.